// Copyright 2017 The Draco Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#ifndef DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_MESH_PREDICTION_SCHEME_GEOMETRIC_NORMAL_DECODER_H_
#define DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_MESH_PREDICTION_SCHEME_GEOMETRIC_NORMAL_DECODER_H_

#include "draco/draco_features.h"

#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_decoder.h"
#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_geometric_normal_predictor_area.h"
#include "draco/core/bit_coders/rans_bit_decoder.h"

namespace draco {

// See MeshPredictionSchemeGeometricNormalEncoder for documentation.
template <typename DataTypeT, class TransformT, class MeshDataT>
class MeshPredictionSchemeGeometricNormalDecoder
    : public MeshPredictionSchemeDecoder<DataTypeT, TransformT, MeshDataT> {
  public:
    using CorrType = typename MeshPredictionSchemeDecoder<DataTypeT, TransformT,
          MeshDataT>::CorrType;
    MeshPredictionSchemeGeometricNormalDecoder(const PointAttribute *attribute,
            const TransformT &transform,
            const MeshDataT &mesh_data)
        : MeshPredictionSchemeDecoder<DataTypeT, TransformT, MeshDataT>(
              attribute, transform, mesh_data),
          predictor_(mesh_data) {}

  private:
    MeshPredictionSchemeGeometricNormalDecoder() {}

  public:
    bool ComputeOriginalValues(const CorrType *in_corr, DataTypeT *out_data,
                               int size, int num_components,
                               const PointIndex *entry_to_point_id_map) override;

    bool DecodePredictionData(DecoderBuffer *buffer) override;

    PredictionSchemeMethod GetPredictionMethod() const override {
        return MESH_PREDICTION_GEOMETRIC_NORMAL;
    }

    bool IsInitialized() const override {
        if (!predictor_.IsInitialized())
            return false;
        if (!this->mesh_data().IsInitialized())
            return false;
        if (!octahedron_tool_box_.IsInitialized())
            return false;
        return true;
    }

    int GetNumParentAttributes() const override {
        return 1;
    }

    GeometryAttribute::Type GetParentAttributeType(int i) const override {
        DRACO_DCHECK_EQ(i, 0);
        (void)i;
        return GeometryAttribute::POSITION;
    }

    bool SetParentAttribute(const PointAttribute *att) override {
        if (att->attribute_type() != GeometryAttribute::POSITION)
            return false;  // Invalid attribute type.
        if (att->num_components() != 3)
            return false;  // Currently works only for 3 component positions.
        predictor_.SetPositionAttribute(*att);
        return true;
    }
    void SetQuantizationBits(int q) {
        octahedron_tool_box_.SetQuantizationBits(q);
    }

  private:
    MeshPredictionSchemeGeometricNormalPredictorArea<DataTypeT, TransformT,
                                                     MeshDataT>
                                                     predictor_;
    OctahedronToolBox octahedron_tool_box_;
    RAnsBitDecoder flip_normal_bit_decoder_;
};

template <typename DataTypeT, class TransformT, class MeshDataT>
bool MeshPredictionSchemeGeometricNormalDecoder<
DataTypeT, TransformT,
           MeshDataT>::ComputeOriginalValues(const CorrType *in_corr,
                   DataTypeT *out_data, int /* size */,
                   int num_components,
const PointIndex *entry_to_point_id_map) {
    this->SetQuantizationBits(this->transform().quantization_bits());
    predictor_.SetEntryToPointIdMap(entry_to_point_id_map);
    DRACO_DCHECK(this->IsInitialized());

    // Expecting in_data in octahedral coordinates, i.e., portable attribute.
    DRACO_DCHECK_EQ(num_components, 2);

    const int corner_map_size = this->mesh_data().data_to_corner_map()->size();

    VectorD<int32_t, 3> pred_normal_3d;
    int32_t pred_normal_oct[2];

    for (int data_id = 0; data_id < corner_map_size; ++data_id) {
        const CornerIndex corner_id =
            this->mesh_data().data_to_corner_map()->at(data_id);
        predictor_.ComputePredictedValue(corner_id, pred_normal_3d.data());

        // Compute predicted octahedral coordinates.
        octahedron_tool_box_.CanonicalizeIntegerVector(pred_normal_3d.data());
        DRACO_DCHECK_EQ(pred_normal_3d.AbsSum(),
                        octahedron_tool_box_.center_value());
        if (flip_normal_bit_decoder_.DecodeNextBit()) {
            pred_normal_3d = -pred_normal_3d;
        }
        octahedron_tool_box_.IntegerVectorToQuantizedOctahedralCoords(
            pred_normal_3d.data(), pred_normal_oct, pred_normal_oct + 1);

        const int data_offset = data_id * 2;
        this->transform().ComputeOriginalValue(
            pred_normal_oct, in_corr + data_offset, out_data + data_offset);
    }
    flip_normal_bit_decoder_.EndDecoding();
    return true;
}

template <typename DataTypeT, class TransformT, class MeshDataT>
bool MeshPredictionSchemeGeometricNormalDecoder<
DataTypeT, TransformT, MeshDataT>::DecodePredictionData(DecoderBuffer
        *buffer) {
    // Get data needed for transform
    if (!this->transform().DecodeTransformData(buffer))
        return false;

#ifdef DRACO_BACKWARDS_COMPATIBILITY_SUPPORTED
    if (buffer->bitstream_version() < DRACO_BITSTREAM_VERSION(2, 2)) {
        uint8_t prediction_mode;
        buffer->Decode(&prediction_mode);

        if (!predictor_.SetNormalPredictionMode(
                    NormalPredictionMode(prediction_mode)))
            return false;
    }
#endif

    // Init normal flips.
    if (!flip_normal_bit_decoder_.StartDecoding(buffer))
        return false;

    return true;
}

}  // namespace draco

#endif  // DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_MESH_PREDICTION_SCHEME_GEOMETRIC_NORMAL_DECODER_H_
